EP0844752A2 - Automatic dispersion compensating optical transmission system - Google Patents
Automatic dispersion compensating optical transmission system Download PDFInfo
- Publication number
- EP0844752A2 EP0844752A2 EP97119658A EP97119658A EP0844752A2 EP 0844752 A2 EP0844752 A2 EP 0844752A2 EP 97119658 A EP97119658 A EP 97119658A EP 97119658 A EP97119658 A EP 97119658A EP 0844752 A2 EP0844752 A2 EP 0844752A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- optical
- signal
- dispersion compensation
- monitoring control
- optical signal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 230000003287 optical effect Effects 0.000 title claims abstract description 205
- 230000005540 biological transmission Effects 0.000 title claims abstract description 93
- 239000006185 dispersion Substances 0.000 title claims abstract description 93
- 238000012544 monitoring process Methods 0.000 claims abstract description 32
- 230000001360 synchronised effect Effects 0.000 claims abstract description 4
- 239000011159 matrix material Substances 0.000 claims description 10
- 230000001172 regenerating effect Effects 0.000 claims description 6
- 238000010276 construction Methods 0.000 description 14
- 238000004891 communication Methods 0.000 description 4
- 239000013307 optical fiber Substances 0.000 description 3
- 239000000835 fiber Substances 0.000 description 2
- 238000000034 method Methods 0.000 description 1
- 230000000644 propagated effect Effects 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/25—Arrangements specific to fibre transmission
- H04B10/2507—Arrangements specific to fibre transmission for the reduction or elimination of distortion or dispersion
- H04B10/2513—Arrangements specific to fibre transmission for the reduction or elimination of distortion or dispersion due to chromatic dispersion
- H04B10/2525—Arrangements specific to fibre transmission for the reduction or elimination of distortion or dispersion due to chromatic dispersion using dispersion-compensating fibres
Definitions
- the present invention relates to an automatic dispersion compensating optical transmission for performing an automatic dispersion compensation by a repeater in a long distance, light-based transmission in which an optical signal transmitted from mainly an optical transmitter through a transmission line is directly amplified by the repeater.
- DCF dispersion compensating fiber
- An optical communication system disclosed in Japanese Patent Application Laid-open No. H7-202798 is one of examples of the known techniques related to the dispersion compensation in a long distance, light-based transmission.
- a long distance, light-based transmission rate is increased by making a length of the DCF used to dispersion compensation a half of a usual length of the DCF.
- a capacity of the optical communication system is increased by applying the dispersion compensation in order to realize the wavelength multiplex transmission.
- the amount of dispersion compensation of the DCF has to be set to an optimal value which depends upon a transmission distance thereof as mentioned above. Therefore, when the transmission line is switched to a preliminary line, it is necessary to set the amount of dispersion compensation again to an optimal value of the preliminary line by replacing the DCF. However, it is impossible in the conventional system to automatically switch between DCF's.
- the length of the DCF used to compensate for the dispersion is made a half of the usual length, it can not be adapted to a case where the amount of dispersion of the transmission line is changed.
- the dispersion compensation is applied for the wavelength multiplex transmission and it is impossible to control the amount of dispersion compensation correspondingly to the transmission lines.
- An object of the present invention is to provide an automatic dispersion compensation type optical transmission system which allows an amount of dispersion compensation of a DCF to be set to an optimal value for each of transmission sections and can be adapted to an automatic switching of transmission lines.
- an automatic dispersion compensation type optical transmission system comprises an optical transmission unit for transmitting an optical signal to a transmission line and a repeater for directly amplifying the optical signal transmitted from the transmission line.
- the optical transmission unit includes optical transmitters for transmitting an optical main signal and a monitoring control optical signal, respectively, a low frequency signal multiplexing circuit for multiplexing low frequency pulse signals each synchronized with the optical main signal and the monitoring control optical signal, an optical preamplifier for directly amplifying the optical main signal and outputting the amplified optical main signal and a WDM coupler for wavelength-synthesizing the amplified optical main signal and the monitoring control optical signal and outputting the synthesized signal as an optical signal and the repeater includes an optical coupler for branching a portion of the optical signal for use to detect a phase difference between the optical main signal and the monitoring control optical signal, a WDM coupler for wavelength-separating the branched optical signal to the optical main signal and the monitoring control optical signal, opto-electric converter circuits for converting the optical main
- the dispersion compensator unit comprises a pair of light branching and confluence setting devices for branching an optical transmission line to a plurality (N) of branch lines and joining a plurality (N) of branch lines to a optical transmission line, a plurality (N) of DCF's having different dispersion compensating amounts and provided in the plurality (N) of the branch lines, respectively, and a control circuit for automatically selecting one of the DCF's having an optimal dispersion compensating amount according to a transmission distance by controlling the light branching and confluence setting devices according to a phase difference between the optical main signal and the monitoring control optical signal.
- the light branching and confluence setting devices of the automatic dispersion compensation type optical transmission system may comprise optical matrix switches provided on an input side and an output side of the DCF's, respectively, or an optical matrix switch provided on the input side of the DCF's and an optical coupler provided on the output side of the DCF's.
- the repeater of the light branching and confluence setting devices of the automatic dispersion compensation type optical transmission system which comprise optical matrix switches provided on an input side and an output side of the DCF's, respectively, or an optical matrix switch provided on the input side of the DCF's and an optical coupler provided on the output side of the DCF's may be a linear repeater or a regenerative repeaters
- the automatic dispersion compensation type optical transmission system of the present invention there is a difference in propagation rate between transmission lines due to the fact that the wavelengths of the optical main signal produced in the optical transmitting unit and the monitoring control optical signal are different from each other. Due to such difference of the propagation rate, a phase difference is provided between the low frequency pulse signals multiplexed with the optical main signal and the monitoring control optical signal, respectively. Therefore, in the repeater, a distance of a transmission section is specified by detecting the phase difference by the phase difference detector circuit and, in the dispersion compensating the light branching and confluence setting devices having the DCF's having different dispersion compensation amounts therebetween are controlled by the control circuit on the basis of a phase difference information.
- the transmission line can be switched to one of the DCF's which has an optimal dispersion compensation amount, making an optimal dispersion compensation possible. Therefore, in the automatic dispersion compensation type optical transmission system according to the present invention, even when the required dispersion compensation amount is changed by a switching of the transmission line, an automatic dispersion compensation becomes optimal.
- Fig. 1 shows a basic construction of an automatic dispersion compensation type optical transmission system according to a first embodiment of the present invention and waveforms of processing signals at main portions thereof.
- the automatic dispersion compensation type optical transmission system is basically composed of an optical transmitting unit 10 for transmitting an optical signal to a transmission line and a linear repeater 11 for directly amplifying the optical signal transmitted from the transmission line.
- the optical transmitting unit 10 includes an optical transmitter 1 for transmitting an optical main signal a and an optical transmitter 2 for transmitting a monitoring control optical signal b, a low frequency signal multiplexing circuit 3 for multiplexing low frequency pulse signals each synchronized with the optical main signal a and the monitoring control optical signal b, an optical preamplifier 4 for directly amplifying the optical main signal a and outputting the amplified optical main signal and a WDM coupler 5 for wavelength-synthesizing the amplified optical main signal and the monitoring control optical signal b and outputting the synthesized signal as an optical signal.
- the linear repeater 11 includes an optical coupler 12 for branching a portion of the optical signal transmitted from the optical transmitting unit 10 through the transmission line for use to detect a phase difference between the optical main signal a and the monitoring control optical signal b, a WDM coupler 13 for wavelength-separating the branched optical signal to the optical main signal a and the monitoring control optical signal b, opto-electric converter circuits 14 and 15 for converting the optical main signal a and the monitoring control optical signal b of the optical signal into electric signals, respectively, low-pass filters (LPF's) 16 and 17 for removing high frequency components of the opto-electrically converted optical main signal and the monitoring control optical signal, respectively, a phase difference detector circuit 18 for detecting a phase difference ⁇ by extracting the low frequency pulse signals multiplexed in the low frequency multiplexing circuit 3 of the optical transmitting unit 10 from the low-pass filtered optical main signal a' and the monitoring control optical signal b', an optical amplifier 19 for directly amplifying the optical signal and outputting the amplified optical signal
- the dispersion compensator unit includes an optical branch setting device 22 optical matrix switch capable of branching a transmission line to a plurality (N) of branch lines, an optical confluence setting device 22' such a optical matrix switch arranged opposite to the optical branch setting device 22 and capable of joining the plurality (N) of branch lines to a transmission line, a plurality (N) of DCF's having mutually different dispersion compensating amounts and provided in the respective branch lines and a control circuit 26 for controlling the optical branch setting device 22 and the optical confluence setting device 22' to automatically select one of the DCF's having an optimal dispersion compensating amount corresponding to a transmission distance determined by the phase difference.
- N is 2 and 2 DCF's 24 and 25 are provided.
- the optical transmitter 1 of the optical transmitting unit 10 may transmit the optical main signal having wavelength of 1.552 ⁇ m and the optical transmitter 2 may be transmits the monitoring control optical signal having wavelength of 1.520 ⁇ m.
- the optical main signal a and the monitoring control optical signal b which are multiplexed with the low frequency pulse signals are wavelength-synthesized by the WDM coupler 5 and the resultant optical signal is transmitted through the transmission line to the linear repeater 11.
- the distance of the transmission section is 80 km which is generally used in the linear repeater and the transmission line is constituted with a usual 1.3 ⁇ m zero dispersion optical fiber (18 psec/km).
- Fig. 2 shows a basic construction of an automatic dispersion compensation type optical transmission system according to a second embodiment of the present invention and waveforms of processing signals at main portions thereof.
- the automatic dispersion compensation type optical transmission system is basically composed of an optical transmitting unit 10 for transmitting an optical signal to a transmission line and a regenerative repeater 11' for directly amplifying the optical signal transmitted from the transmission line.
- the optical transmitting unit 10 has the same construction as that of the first embodiment and the regenerative repeater 11' has a construction equivalent to the linear repeater 11 of the first embodiment.
- the automatic dispersion compensation type optical transmission system functions similarly to the system of the first embodiment and it is possible to automatically perform the optimal dispersion compensation.
- Fig. 3 shows a basic construction of an automatic dispersion compensation type optical transmission system according to a third embodiment of the present invention and waveforms of processing signals at main portions thereof.
- the automatic dispersion compensation type optical transmission system is basically composed of an optical transmitting unit 10 for transmitting an optical signal to a transmission line and a linear repeater 11 for directly amplifying the optical signal transmitted from the transmission line.
- the optical transmitting unit 10 is the same as that of the first embodiment and the linear repeater 11 has the same construction as that of the first embodiment except that the optical branching and confluence devices are an optical matrix switch 22 provided on the input side of the DCF's 24 and 25 and an optical coupler 23 provided on the output side thereof.
- the automatic dispersion compensation type optical transmission system of the third embodiment is capable of automatically perform the optimal dispersion compensation as in the first or second embodiment.
- Fig. 4 shows a basic construction of an automatic dispersion compensation type optical transmission system according to a fourth embodiment of the present invention and waveforms of processing signals at main portions thereof.
- the automatic dispersion compensation type optical transmission system is basically composed of an optical transmitting unit 10 for transmitting an optical signal to a transmission line and a regenerative repeater 11' for directly amplifying the optical signal transmitted from the transmission line.
- the optical transmitting unit 10 is the same as that of the first embodiment and the regenerative repeater 11' has the same construction as that of the third embodiment.
- the automatic dispersion compensation type optical transmission system of the fourth embodiment is capable of automatically perform the optimal dispersion compensation as in the first to third embodiments.
- dispersion compensator unit of the automatic dispersion compensation type optical transmission system has been described as having the construction adaptable to N dispersion compensation amounts with N being 2, it is possible to expand the construction adaptable to three or more dispersion compensation amounts by increasing the number N of the branch lines and hence the DCF's. In any case, it is possible to perform the optimal dispersion compensation regardless of transmission distance.
- the automatic dispersion compensation type optical transmission system is provided with the dispersion compensator unit for automatically selecting one of the DCF's adaptable to a number of amounts of dispersion compensation, it is possible to set an optimal amount of dispersion compensation of the DCF according to a transmission section and further to easily adapt it to an automatic switching of transmission line.
Abstract
In an optical transmission system in which an optical main signal and a monitoring
control optical signal are wavelength-multiplexed and transmitted from a transmitter and
the optical signal is directly amplified by a repeater and transmitted, low frequency pulse
signals which are synchronized with the respective optical main signal and monitoring
control signal are multiplexed with each others, a distance of a transmission section is
specified by a phase difference between the low frequency pulse signals according to a
difference in propagation rate of a transmission line due to a difference of wavelength
between the optical main signal and the monitoring control signal and the optimal
dispersion compensation is made possible even when a required dispersion compensation
is changed due to a change of the transmission line by switching the optical transmission
line to a DCF having an optimal amount of dispersion compensation.
Description
The present invention relates to an automatic dispersion compensating optical
transmission for performing an automatic dispersion compensation by a repeater in a long
distance, light-based transmission in which an optical signal transmitted from mainly an
optical transmitter through a transmission line is directly amplified by the repeater.
In a long distance, light-based transmission which uses a high dispersion optical fiber
as a transmission line, a signal waveform distortion has occurred due to dispersion and a
correct waveform transmission has become impossible. Therefore, an application of a
dispersion compensation by means of a dispersion compensation device such as a
dispersion compensating fiber (referred to as "DCF", hereinafter) has become
indispensable. A required amount of dispersion compensation depends upon a distance of
transmission and a dispersion characteristics of optical fiber.
An optical communication system disclosed in Japanese Patent Application Laid-open
No. H7-202798 is one of examples of the known techniques related to the dispersion
compensation in a long distance, light-based transmission. In this optical communication
system, a long distance, light-based transmission rate is increased by making a length of the
DCF used to dispersion compensation a half of a usual length of the DCF. Further, in an
optical wavelength multiplex transmission system and an optical dispersion compensation
system disclosed in Japanese Patent Application Laid-open No. H7-107069, a capacity of
the optical communication system is increased by applying the dispersion compensation in
order to realize the wavelength multiplex transmission.
In general, the amount of dispersion compensation of the DCF has to be set to an
optimal value which depends upon a transmission distance thereof as mentioned above.
Therefore, when the transmission line is switched to a preliminary line, it is necessary to
set the amount of dispersion compensation again to an optimal value of the preliminary
line by replacing the DCF. However, it is impossible in the conventional system to
automatically switch between DCF's.
Incidentally, since, in the case of the optical communication system disclosed in the
aforementioned Japanese Patent Application Laid-open No. H7-202798, the length of the
DCF used to compensate for the dispersion is made a half of the usual length, it can not be
adapted to a case where the amount of dispersion of the transmission line is changed.
Further, in the case of the dispersion compensation system disclosed in the aforementioned
Japanese Patent Application Laid-open No. H7-107069, the dispersion compensation is
applied for the wavelength multiplex transmission and it is impossible to control the
amount of dispersion compensation correspondingly to the transmission lines.
An object of the present invention is to provide an automatic dispersion
compensation type optical transmission system which allows an amount of dispersion
compensation of a DCF to be set to an optimal value for each of transmission sections and
can be adapted to an automatic switching of transmission lines.
According to the present invention, an automatic dispersion compensation type
optical transmission system comprises an optical transmission unit for transmitting an
optical signal to a transmission line and a repeater for directly amplifying the optical signal
transmitted from the transmission line. The optical transmission unit includes optical
transmitters for transmitting an optical main signal and a monitoring control optical signal,
respectively, a low frequency signal multiplexing circuit for multiplexing low frequency
pulse signals each synchronized with the optical main signal and the monitoring control
optical signal, an optical preamplifier for directly amplifying the optical main signal and
outputting the amplified optical main signal and a WDM coupler for wavelength-synthesizing
the amplified optical main signal and the monitoring control optical signal and
outputting the synthesized signal as an optical signal and the repeater includes an optical
coupler for branching a portion of the optical signal for use to detect a phase difference
between the optical main signal and the monitoring control optical signal, a WDM coupler
for wavelength-separating the branched optical signal to the optical main signal and the
monitoring control optical signal, opto-electric converter circuits for converting the optical
main signal and the monitoring control optical signal of the optical signal into electric
signals, respectively, a phase difference detector circuit for extracting the low frequency
pulse signals multiplexed in the optical transmitting unit from the opto-electrically
converted optical main signal and the monitoring control optical signal and detecting a
phase difference therebetween, an optical amplifier for directly amplifying the optical
signal and outputting the amplified optical signal and a dispersion compensator unit for
automatically compensating a dispersion of the amplified optical signal.
Further, in the automatic dispersion compensation type optical transmission system
according to the present invention, the dispersion compensator unit comprises a pair of
light branching and confluence setting devices for branching an optical transmission line to a
plurality (N) of branch lines and joining a plurality (N) of branch lines to a optical
transmission line, a plurality (N) of DCF's having different dispersion compensating
amounts and provided in the plurality (N) of the branch lines, respectively, and a control
circuit for automatically selecting one of the DCF's having an optimal dispersion
compensating amount according to a transmission distance by controlling the light
branching and confluence setting devices according to a phase difference between the
optical main signal and the monitoring control optical signal.
Further, according to the present invention, the light branching and confluence setting
devices of the automatic dispersion compensation type optical transmission system may
comprise optical matrix switches provided on an input side and an output side of the
DCF's, respectively, or an optical matrix switch provided on the input side of the DCF's
and an optical coupler provided on the output side of the DCF's.
In addition, according to the present invention, the repeater of the light branching and
confluence setting devices of the automatic dispersion compensation type optical
transmission system which comprise optical matrix switches provided on an input side and
an output side of the DCF's, respectively, or an optical matrix switch provided on the
input side of the DCF's and an optical coupler provided on the output side of the DCF's
may be a linear repeater or a regenerative repeaters
In the automatic dispersion compensation type optical transmission system of the
present invention, there is a difference in propagation rate between transmission lines due
to the fact that the wavelengths of the optical main signal produced in the optical
transmitting unit and the monitoring control optical signal are different from each other.
Due to such difference of the propagation rate, a phase difference is provided between the
low frequency pulse signals multiplexed with the optical main signal and the monitoring
control optical signal, respectively. Therefore, in the repeater, a distance of a transmission
section is specified by detecting the phase difference by the phase difference detector
circuit and, in the dispersion compensating the light branching and confluence setting
devices having the DCF's having different dispersion compensation amounts therebetween
are controlled by the control circuit on the basis of a phase difference information. Thus,
even when the dispersion compensation amount is changed by a change of the transmission
line, the transmission line can be switched to one of the DCF's which has an optimal
dispersion compensation amount, making an optimal dispersion compensation possible.
Therefore, in the automatic dispersion compensation type optical transmission system
according to the present invention, even when the required dispersion compensation
amount is changed by a switching of the transmission line, an automatic dispersion
compensation becomes optimal.
The automatic dispersion compensation type optical transmission system according
to the present invention will be described in detail with reference to preferred embodiments
shown in the attached drawings.
Fig. 1 shows a basic construction of an automatic dispersion compensation type
optical transmission system according to a first embodiment of the present invention and
waveforms of processing signals at main portions thereof.
The automatic dispersion compensation type optical transmission system is
basically composed of an optical transmitting unit 10 for transmitting an optical signal to a
transmission line and a linear repeater 11 for directly amplifying the optical signal
transmitted from the transmission line.
The optical transmitting unit 10 includes an optical transmitter 1 for transmitting an
optical main signal a and an optical transmitter 2 for transmitting a monitoring control
optical signal b, a low frequency signal multiplexing circuit 3 for multiplexing low
frequency pulse signals each synchronized with the optical main signal a and the
monitoring control optical signal b, an optical preamplifier 4 for directly amplifying the
optical main signal a and outputting the amplified optical main signal and a WDM coupler
5 for wavelength-synthesizing the amplified optical main signal and the monitoring control
optical signal b and outputting the synthesized signal as an optical signal.
The linear repeater 11 includes an optical coupler 12 for branching a portion of the
optical signal transmitted from the optical transmitting unit 10 through the transmission
line for use to detect a phase difference between the optical main signal a and the
monitoring control optical signal b, a WDM coupler 13 for wavelength-separating the
branched optical signal to the optical main signal a and the monitoring control optical signal
b, opto- electric converter circuits 14 and 15 for converting the optical main signal a and the
monitoring control optical signal b of the optical signal into electric signals, respectively,
low-pass filters (LPF's) 16 and 17 for removing high frequency components of the opto-electrically
converted optical main signal and the monitoring control optical signal,
respectively, a phase difference detector circuit 18 for detecting a phase difference by
extracting the low frequency pulse signals multiplexed in the low frequency multiplexing
circuit 3 of the optical transmitting unit 10 from the low-pass filtered optical main signal a'
and the monitoring control optical signal b', an optical amplifier 19 for directly amplifying
the optical signal and outputting the amplified optical signal and a dispersion compensator
unit for automatically compensating a dispersion of the amplified optical signal.
The dispersion compensator unit includes an optical branch setting device 22 optical
matrix switch capable of branching a transmission line to a plurality (N) of branch lines, an
optical confluence setting device 22' such a optical matrix switch arranged opposite to the
optical branch setting device 22 and capable of joining the plurality (N) of branch lines to a
transmission line, a plurality (N) of DCF's having mutually different dispersion
compensating amounts and provided in the respective branch lines and a control circuit 26
for controlling the optical branch setting device 22 and the optical confluence setting device
22' to automatically select one of the DCF's having an optimal dispersion compensating
amount corresponding to a transmission distance determined by the phase difference. In
the shown embodiment, N is 2 and 2 DCF's 24 and 25 are provided.
In more detail, the optical transmitter 1 of the optical transmitting unit 10 may
transmit the optical main signal having wavelength of 1.552 µm and the optical transmitter
2 may be transmits the monitoring control optical signal having wavelength of 1.520 µm.
The optical main signal a and the monitoring control optical signal b which are multiplexed
with the low frequency pulse signals are wavelength-synthesized by the WDM coupler 5
and the resultant optical signal is transmitted through the transmission line to the linear
repeater 11. In this embodiment, it is assumed that the distance of the transmission section
is 80 km which is generally used in the linear repeater and the transmission line is
constituted with a usual 1.3 µm zero dispersion optical fiber (18 psec/km).
On the other hand, for the linear repeater 11, since the wavelength dispersion of the
optical signal propagated through the 1.3 µm zero dispersion fiber 80 km long starts in a
wavelength range of 1.5 µm, there is a phase difference = (18 psec/nm/km) x 32 nm x 80
km = 46 nsec produced between the optical signal transmitted from the optical transmitter
1 and the monitoring control optical signal transmitted from the optical transmitter 2. One
of the DCF's 24 and 25 which is suitable for the amount of dispersion compensation of the
transmission line is selected by detecting this phase difference by means of the phase
difference detector circuit 18 and controlling the opposite optical matrix switches 22 and
22' by means of the control circuit 26 of the dispersion compensator unit. Assuming that
the DCF 24 is for 80 km and the DCF 25 is for 60 km, it is possible to automatically
obtain the optimal dispersion compensation when the transmission distance is switched
from 80 km to 60 km.
Fig. 2 shows a basic construction of an automatic dispersion compensation type
optical transmission system according to a second embodiment of the present invention
and waveforms of processing signals at main portions thereof.
The automatic dispersion compensation type optical transmission system is
basically composed of an optical transmitting unit 10 for transmitting an optical signal to a
transmission line and a regenerative repeater 11' for directly amplifying the optical signal
transmitted from the transmission line.
The optical transmitting unit 10 has the same construction as that of the first
embodiment and the regenerative repeater 11' has a construction equivalent to the linear
repeater 11 of the first embodiment.
Therefore, the automatic dispersion compensation type optical transmission system
functions similarly to the system of the first embodiment and it is possible to
automatically perform the optimal dispersion compensation.
Fig. 3 shows a basic construction of an automatic dispersion compensation type
optical transmission system according to a third embodiment of the present invention and
waveforms of processing signals at main portions thereof.
The automatic dispersion compensation type optical transmission system is
basically composed of an optical transmitting unit 10 for transmitting an optical signal to a
transmission line and a linear repeater 11 for directly amplifying the optical signal
transmitted from the transmission line. The optical transmitting unit 10 is the same as that
of the first embodiment and the linear repeater 11 has the same construction as that of the
first embodiment except that the optical branching and confluence devices are an optical
matrix switch 22 provided on the input side of the DCF's 24 and 25 and an optical coupler
23 provided on the output side thereof.
Therefore, the automatic dispersion compensation type optical transmission system
of the third embodiment is capable of automatically perform the optimal dispersion
compensation as in the first or second embodiment.
Fig. 4 shows a basic construction of an automatic dispersion compensation type
optical transmission system according to a fourth embodiment of the present invention and
waveforms of processing signals at main portions thereof.
The automatic dispersion compensation type optical transmission system is
basically composed of an optical transmitting unit 10 for transmitting an optical signal to a
transmission line and a regenerative repeater 11' for directly amplifying the optical signal
transmitted from the transmission line. The optical transmitting unit 10 is the same as that
of the first embodiment and the regenerative repeater 11' has the same construction as that
of the third embodiment.
Therefore, the automatic dispersion compensation type optical transmission system
of the fourth embodiment is capable of automatically perform the optimal dispersion
compensation as in the first to third embodiments.
Although the dispersion compensator unit of the automatic dispersion compensation
type optical transmission system according to any of the first to fourth embodiments has
been described as having the construction adaptable to N dispersion compensation
amounts with N being 2, it is possible to expand the construction adaptable to three or
more dispersion compensation amounts by increasing the number N of the branch lines and
hence the DCF's. In any case, it is possible to perform the optimal dispersion
compensation regardless of transmission distance.
As described hereinbefore, since the automatic dispersion compensation type optical
transmission system according to the present invention is provided with the dispersion
compensator unit for automatically selecting one of the DCF's adaptable to a number of
amounts of dispersion compensation, it is possible to set an optimal amount of dispersion
compensation of the DCF according to a transmission section and further to easily adapt it
to an automatic switching of transmission line.
Claims (5)
- An automatic dispersion compensation type optical transmission system comprising:an optical transmission unit for transmitting an optical signal to a transmission line, said optical transmission unit comprising:optical transmitters for transmitting an optical main signal and a monitoring control optical signal, respectively;a low frequency signal multiplexing circuit for multiplexing low frequency pulse signals each synchronized with the optical main signal and the monitoring control optical signal;an optical preamplifier for directly amplifying the optical main signal and outputting the amplified optical main signal; anda WDM coupler for wavelength-synthesizing the amplified optical main signal and the monitoring control optical signal and outputting the synthesized signal as an optical signal; anda repeater for directly amplifying the optical signal; transmitted through said transmission line, said repeater comprising:an optical coupler for branching a portion of the optical signal to detect a phase difference between the optical main signal and the monitoring control optical signal;a WDM coupler for wavelength-separating the branched optical signal to the optical main signal and the monitoring control optical signal;opto-electric converter circuits for converting the optical main signal and the monitoring control optical signal of the optical signal into electric signals, respectively;a phase difference detector circuit for extracting the low frequency pulse signals multiplexed in said optical transmitting unit from the opto-electrically converted optical main signal and the monitoring control optical signal and detecting a phase difference therebetween;an optical amplifier for directly amplifying the optical signal and outputting the amplified optical signal; anda dispersion compensator unit for automatically compensating a dispersion of the amplified optical signal.
- An automatic dispersion compensation type optical transmission system as claimed in claim 1, wherein said dispersion compensator unit comprises a pair of light branching and confluence setting devices for branching an optical transmission line to a plurality (N) of branch lines and joining a plurality (N) of branch lines to an optical transmission line, a plurality (N) of DCF's having different dispersion compensating amounts and provided in the plurality (N) of said branch lines, respectively, and a control circuit for automatically selecting one of said DCF's having an optimal dispersion compensating amount according to a transmission distance by controlling said light branching and confluence setting devices according to a phase difference between the optical main signal and the monitoring control optical signal, where N is an integer larger than 1.
- An automatic dispersion compensation type optical transmission system as claimed in claim 2, wherein said light branching and confluence setting devices comprises optical matrix switches provided on an input side and an output side of said DCF's, respectively.
- An automatic dispersion compensation type optical transmission system as claimed in claim 2, wherein said light branching and confluence setting devices comprises an optical matrix switch provided on an input side of said DCF's and an optical coupler provided on an output side of said DCF's.
- An automatic dispersion compensation type optical transmission system as claimed in any of claims 1 to 4, wherein said repeater comprises a linear repeater or a regenerative repeater.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8313594A JPH10163962A (en) | 1996-11-25 | 1996-11-25 | Automatic dispersion compensation optical transmission system |
| JP313594/96 | 1996-11-25 | ||
| JP31359496 | 1996-11-25 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0844752A2 true EP0844752A2 (en) | 1998-05-27 |
| EP0844752A3 EP0844752A3 (en) | 2000-12-20 |
Family
ID=18043203
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP97119658A Withdrawn EP0844752A3 (en) | 1996-11-25 | 1997-11-10 | Automatic dispersion compensating optical transmission system |
Country Status (3)
| Country | Link |
|---|---|
| US (1) | US6055082A (en) |
| EP (1) | EP0844752A3 (en) |
| JP (1) | JPH10163962A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2001027674A2 (en) * | 1999-10-15 | 2001-04-19 | Scc Special Communication Cables Gmbh & Co. Kg | Optical monitoring device |
| US6317583B1 (en) * | 1997-07-25 | 2001-11-13 | Trw Inc. | Telecommunications satellite channelizer |
| DE10130993C1 (en) * | 2001-06-27 | 2003-04-24 | Siemens Ag | Arrangement for optimizing quality of wavelength division multiplex signal with residual dispersion has decoupler, module for adjusting residual dispersion of signal, signal quality detector |
Families Citing this family (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3551407B2 (en) * | 1998-02-16 | 2004-08-04 | 富士通株式会社 | WDM optical transmission system |
| JP4517423B2 (en) * | 1999-12-03 | 2010-08-04 | 住友電気工業株式会社 | Dispersion compensation module, line switching device, and optical communication system |
| US7536108B2 (en) * | 2001-06-29 | 2009-05-19 | Nippon Telegraph & Telephone Corporation | High precision chromatic dispersion measuring method and automatic dispersion compensating optical link system that uses this method |
| JP2004254018A (en) * | 2003-02-19 | 2004-09-09 | Fujitsu Ltd | Dispersion compensating device and wavelength division multiplex communication system using the same |
| US7519295B2 (en) * | 2003-10-30 | 2009-04-14 | Tyco Telecommunications (Us) Inc. | Apparatus and method for commissioning an optical transmission system |
| JP4517747B2 (en) * | 2004-06-28 | 2010-08-04 | 日本電気株式会社 | Wavelength multiplexing transmission apparatus and wavelength extension method thereof |
| JP4516389B2 (en) * | 2004-09-08 | 2010-08-04 | 関西電力株式会社 | WDM transmission system |
| US7917084B2 (en) * | 2006-07-21 | 2011-03-29 | Wilson Electronics | Cellular repeater watermarking system and method |
| JP5747629B2 (en) | 2011-04-18 | 2015-07-15 | 富士通株式会社 | Optical transmission device and optical switch device |
| US10404397B2 (en) * | 2015-12-23 | 2019-09-03 | Adva Optical Networking Se | Wavelength division multiplexed telecommunication system with automatic compensation of chromatic dispersion |
| US10122460B2 (en) | 2017-01-13 | 2018-11-06 | Adva Optical Networking Se | Method and apparatus for automatic compensation of chromatic dispersion |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH07107069A (en) * | 1993-08-10 | 1995-04-21 | Fujitsu Ltd | Optical wavelength multiplex transmission system and optical dispersion compensation system |
Family Cites Families (23)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4307469A (en) * | 1980-04-18 | 1981-12-22 | Harris Corporation | Injection laser diode digital transmitter having signal quality monitoring arrangement |
| US4736359A (en) * | 1986-05-06 | 1988-04-05 | Itt Defense Communications , A Division Of Itt Corporation | Single fiber optical communication system |
| US5060307A (en) * | 1986-06-02 | 1991-10-22 | El Sherif Mahmoud A | Apparatus and a method comprising an optical fiber modulator, coupler, switch, sensor and distribution system |
| US4972513A (en) * | 1987-07-23 | 1990-11-20 | Kokusai Denshin Denwa Kabushiki Kaisha | Multi-point optical amplification repeating system |
| JPH01120137A (en) * | 1987-11-02 | 1989-05-12 | Hitachi Ltd | Optical receiver |
| JPH02246442A (en) * | 1989-03-17 | 1990-10-02 | Fujitsu Ltd | Phase compensation system for optical repeater |
| US5076658A (en) * | 1990-04-30 | 1991-12-31 | Unisys Corporation | Non-linear optical polymeric fiber waveguides |
| JP2913784B2 (en) * | 1990-06-28 | 1999-06-28 | 株式会社デンソー | Power supply for vehicles |
| US5225922A (en) * | 1991-11-21 | 1993-07-06 | At&T Bell Laboratories | Optical transmission system equalizer |
| JPH06224849A (en) * | 1993-01-22 | 1994-08-12 | Furukawa Electric Co Ltd:The | Receiver |
| SE501070C2 (en) * | 1993-03-26 | 1994-11-07 | Ericsson Telefon Ab L M | Dispersion compensation system and method in high speed fiber optic systems |
| JP3269713B2 (en) * | 1993-09-03 | 2002-04-02 | 株式会社日立製作所 | Optical transmission system |
| JP3266897B2 (en) * | 1993-11-01 | 2002-03-18 | 住友電気工業株式会社 | Chromatic dispersion generator, method of manufacturing the same, and chromatic dispersion compensator |
| US5473719A (en) * | 1993-11-15 | 1995-12-05 | At&T Corp. | Optical dispersion compensator |
| JP3177361B2 (en) * | 1993-11-17 | 2001-06-18 | 松下電器産業株式会社 | Optical transmitter |
| US5404413A (en) * | 1993-12-14 | 1995-04-04 | At&T Corp. | Optical circulator for dispersion compensation |
| JPH07245584A (en) * | 1994-03-04 | 1995-09-19 | Sumitomo Electric Ind Ltd | Wavelength dispersion compensating device |
| EP0684709B1 (en) * | 1994-05-25 | 2002-10-02 | AT&T Corp. | Optical communications system with adjustable dispersion compensation |
| JP3382716B2 (en) * | 1994-06-14 | 2003-03-04 | 松下電器産業株式会社 | Optical transmission system |
| JP3293738B2 (en) * | 1995-04-14 | 2002-06-17 | 日本電信電話株式会社 | Phase-locked system and constituent devices of the phase-locked system |
| JP3327081B2 (en) * | 1995-12-04 | 2002-09-24 | ケイディーディーアイ株式会社 | Optical transmission system |
| JP2991105B2 (en) * | 1996-03-27 | 1999-12-20 | 日本電気株式会社 | Optical transmitter |
| JP3464744B2 (en) * | 1996-06-03 | 2003-11-10 | 日本電信電話株式会社 | Automatic equalization system |
-
1996
- 1996-11-25 JP JP8313594A patent/JPH10163962A/en active Pending
-
1997
- 1997-11-10 EP EP97119658A patent/EP0844752A3/en not_active Withdrawn
- 1997-11-18 US US08/972,817 patent/US6055082A/en not_active Expired - Fee Related
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH07107069A (en) * | 1993-08-10 | 1995-04-21 | Fujitsu Ltd | Optical wavelength multiplex transmission system and optical dispersion compensation system |
Non-Patent Citations (2)
| Title |
|---|
| PATENT ABSTRACTS OF JAPAN vol. 1995, no. 07, 31 August 1995 (1995-08-31) & JP 07 107069 A (FUJITSU LTD), 21 April 1995 (1995-04-21) -& US 5 602 666 A (ISHIKAWA ET AL.) 11 February 1997 (1997-02-11) * |
| SANO A ET AL: "Automatic dispersion equalization by monitoring extracted clock power level in a 40-GBit/s 200-km transmission line" PROCEEDINGS OF THE EUROPEAN CONFERENCE ON OPTICAL COMMUNICATION, 1996, XP002126413 * |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6317583B1 (en) * | 1997-07-25 | 2001-11-13 | Trw Inc. | Telecommunications satellite channelizer |
| WO2001027674A2 (en) * | 1999-10-15 | 2001-04-19 | Scc Special Communication Cables Gmbh & Co. Kg | Optical monitoring device |
| WO2001027674A3 (en) * | 1999-10-15 | 2001-12-06 | Scc Special Comm Cables Gmbh | Optical monitoring device |
| DE10130993C1 (en) * | 2001-06-27 | 2003-04-24 | Siemens Ag | Arrangement for optimizing quality of wavelength division multiplex signal with residual dispersion has decoupler, module for adjusting residual dispersion of signal, signal quality detector |
Also Published As
| Publication number | Publication date |
|---|---|
| US6055082A (en) | 2000-04-25 |
| EP0844752A3 (en) | 2000-12-20 |
| JPH10163962A (en) | 1998-06-19 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US6925262B2 (en) | Method and system for compensating chromatic dispersion | |
| EP1536258B1 (en) | Optical transmission system, optical multiplexing transmission system, and related peripheral techniques | |
| US5956440A (en) | Optical transmission line for wavelength division multiplexed optical signals | |
| US6055082A (en) | Optical transmission system | |
| EP0847158A2 (en) | An optical wavelength multiplexing and demultiplexing device and an optical transmission system using the same | |
| JP2002517125A (en) | Two-way dispersion compensation system | |
| US6771854B2 (en) | Optical transmission system and optical coupler/branching filter | |
| EP0902560A2 (en) | Method and apparatus for optimizing dispersion in an optical fiber transmission line in accordance with an optical signal power level | |
| EP1389841A2 (en) | Optical tranmission system, optical transmission line and optical transmitter | |
| US5917623A (en) | Wavelength division multiplexing systems | |
| JP3771830B2 (en) | Optical wavelength division multiplexing transmission system with automatic dispersion compensation circuit | |
| US5777764A (en) | Transmission station, intermediate repeater and receiver station for a fibre-optic communications-transmission system | |
| WO1998049794A3 (en) | Low loss, optical add/drop wdm node | |
| EP1241809A1 (en) | Optical transmission system using dispersion compensating optical transmission line | |
| JP3370595B2 (en) | Preset type automatic equalizer | |
| US7221872B2 (en) | On-line dispersion compensation device for a wavelength division optical transmission system | |
| EP1722495B1 (en) | Method of transmitting an optical signal in an optical transmission system and optical transmission system for implementing such a method | |
| US6684004B1 (en) | Optical demultiplexer circuit and demultiplexer device and optical wavelength division multiplex circuit | |
| US20010022684A1 (en) | Optical amplifier and wavelength multiplexing optical transmission system | |
| JPH09116493A (en) | Wavelength multiplex transmission system | |
| JP3408378B2 (en) | Optical repeater amplifier | |
| JP2000236298A (en) | Automatic dispersion compensating circuit and optical transmission system using the same | |
| EP1415418B1 (en) | An apparatus and method for multiplexing and/or demultiplexing optical signals having substantially equal dispersion | |
| KR100319737B1 (en) | Signal power monitoring apparatus and method for wavelength division multipleed signals using the reverse path of arrayed waveguide grating | |
| US20040141749A1 (en) | Optical receiver and optical add/drop apparatus |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
| AK | Designated contracting states |
Kind code of ref document: A2 Designated state(s): DE FR GB IT |
|
| AX | Request for extension of the european patent |
Free format text: AL;LT;LV;MK;RO;SI |
|
| PUAL | Search report despatched |
Free format text: ORIGINAL CODE: 0009013 |
|
| AK | Designated contracting states |
Kind code of ref document: A3 Designated state(s): AT BE CH DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE |
|
| AX | Request for extension of the european patent |
Free format text: AL;LT;LV;MK;RO;SI |
|
| RIC1 | Information provided on ipc code assigned before grant |
Free format text: 7H 04B 10/18 A, 7H 04B 10/08 B |
|
| 17P | Request for examination filed |
Effective date: 20001108 |
|
| AKX | Designation fees paid |
Free format text: DE FR GB IT |
|
| STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN |
|
| 18D | Application deemed to be withdrawn |
Effective date: 20030603 |